Oh u said "old" rpgs in that case if u like traditional turn based rpgs try Bof 3,if ur looking for an awome story theres tales of the abyss(haven't played this one exactly although the stroy seems cool to me) and ofcourse if u haven't yet u should definitely play StarOcean3.
Pretty much any RPG from the PSX era. Even the old Squaresoft RPGs that largely dominated the Playstation market weren't really considered mainstream except for FF7.
Ok, so it hasnt been stated here, but it is an RPG and it does have games in sony systems... I would suggest the Legacy of Ys Series. The first two games remastered for PC are the best. However Tales of Felghana a remake of the 3rd game for PSP/PC is also good but not AS good. The other ones in the series are also fantastic. It's an action RPG similar to Legend of Zelda. But in my opinion all together a bit better. The first two games can also be found on a single cart for the DS... but personally while it is a faithfull remake, it doesnt capture the glory of the series as well as the PC remake.
.hack//G.U series. The battle system is really unique as well with everything else in it, I've got to say one of the best series I've ever played.
I was planning on playing the original .hack series and then the g.u series haven't player either yet though.
Resonance of Fate for the PS3. It was largely overshadowed by the release of FFXIII, and in many regards, it's a breath of fresh air compared to the overly restrictive-hold-your-hand kind of gameplay that FFXIII has. Mind you, it really doesn't baby you through any of the mechanics, and it does a somewhat poor job of explaining them. At least the mechanics aren't being shoved down my throat every 5 seconds...I guess that's the double-edged sword... There's also Folklore for the PS3 although this one is more action-RPG rather than turn based. And then there's Valkyria Chronicles, which is more along the lines of strategy-RPG.